【作者】 李凯锋；

【导师】 刘民英；

【作者基本信息】 郑州大学 ， 材料学， 2011， 硕士

【摘要】 作为耐热性材料,半芳香尼龙由于具有优良的机械性能、耐热性和尺寸稳定性等特点,应用越来越广泛。目前,已经工业化生产的半芳香尼龙品种主要有聚对苯二甲酰己二胺(PA6T)和聚对苯二甲酰壬二胺(PA9T)。但是PA6T的熔点高过其热分解温度,不能进行熔融加工成型；而PA9T的生产成本过高,这些都在一定程度上限制了它们的广泛应用。因此,有必要研究开发价格低廉、合成过程环保的新型高强度、高耐热尼龙。近年来,一种新型的长碳链半芳香尼龙聚对苯二甲酰十二碳二胺(PA12T)已经在实验室阶段开发成功。研究发现,PA12T是一种综合性能优于PA6T和PA9T的耐热性尼龙新品种,将来有望取代PA9T在多领域得到应用。但是,由于PA12T的熔点和粘度很高,导致其聚合产物不能实现聚合釜底部的正常出料,这使其工业化进程受到了很大的影响。本实验室已经分别通过水溶液法和有机溶剂法成功获得了粉末状的PA12T,为PA12T的工业化生产奠定了基础。然而,在该工艺条件下得到的粉末状PA12T的分子量太低,表现为熔点和粘度低,不能进行成型加工。本论文深入研究了PA12T的制备工艺,在保证产品为均匀颗粒状态的前提下,制备出了较高分子量的PA12T,产物熔点为310℃。研究了溶剂加入量、溶剂纯度、抗氧剂等对PA12T分子量的影响规律,研究发现,对于2L的聚合釜,加入110mL热媒介乙醇比较合适,并且当乙醇的质量分数达到95%以上时,其浓度的变化对产物分子量的影响开始减弱；抗氧剂亚磷酸的加入,有利于提高产物的分子量。最后对制得的PA12T样品的结构与性能进行了分析表征,研究发现,新工艺条件下合成的PA12T具有较好的力学性能；运用DMTA技术测试出来的PA12T的玻璃化转变温度为144℃,用阿仑尼乌斯公式计算了PA12T各个转变对应的活化能；采用DSC方法研究了半芳香尼龙PA12T的等温结晶过程及其动力学,确定了PA12T等温结晶时的Avrami指数n值,用阿仑尼乌斯方程计算了PA12T的等温结晶活化能。更多还原

【Abstract】 Due to the excellent mechanical properties, heat resistance and dimensional stability, semiaromatic polyamides are more and more widely used. Currently, there are mainly two kinds of industrialized semiaromatic polyamides, polyhexamethylene terephthalamide (PA6T) and polynonamethylene tereph thalamide (PA9T). But, PA6T cannot be processed by melting method because its melting point is higher than the thermal decomposition temperature, and PA9T has high costs, which, to some extent, limit their wide application. Therefore, it is of great significance to synthesize novel,(?)w-cost and environment-friendly semiaromatic polyamides with high strength and high heat resistant. Recently, a novel long chain semiaromatic polyamide, poly(dodecamethylene terephthalamide) (PA12T), has been successfully prepared in the laboratory. It is found that the comprehensive performance of PA12T is superior to these of PA6T and PA9T. And it is expected to replace PA9T in many fields in the future.However, the high melting point and viscosity of PA12T lead to discharge difficultily, which makes its industrialization process greatly affected. We have obtained PA12T powders successfully in aqueous solution and organic solvent respectively. Nevertheless, the molecular weight of PA12T obtained under this condition is too low to be processed.The preparation process of PA12T was studied in this thesis. The granular PA12T with high molecular weight was prepared, and its melting point was 310℃. The effect of the amount of solvent, solvent purity and antioxidants on the molecular weight of PA12T was also studied. It was found that, it was better to add 110 mL ethanol as solvent for the 2 L kettle, and changes in the concentration started to diminish the impact on the molecular weight of PA12T when the ethanol mass fraction was above 95%. The addition of antioxidant, phosphorous acid, helped to improve the molecular weight of PA12T. Then the structure and properties of obtained PA12T were characterized. The results showed that the PA12T synthesized under new process had good mechanical properties. The glass transition temperature of PA12T tested by DMTA was 144℃The corresponding activation energy of PA12T was calculated through Arrhenius formula. The isothermal crystallization process and its kinetics were also investigated using DSC method. The Avrami index n and activation energy of PA12T under isothermal crystallization were calculated, respectively.更多还原